"Scalars leaked: 1" occurs for each ref or a hash (replace $dummy with %dummy in above script) that is passed as argument to "B::c".

"Attempt to free unreferenced scalar" always happens in above example when we pass a variable (of any type) in one process to a sub in another module when it is run as a thread.

In all above cases, arguments have been initialized before creating threads. In "B::c", it also doesn't matter if those arguments appear as lef-side or right-side (the semaphore and queue definitely change their content and I also tried not to use any argument in "B::c" or just print out some scalar or size of some non-scalar.).

So, is this a problem of my script or a bug or some friendly message that can be safely ignored? Any comments? Thanks!